TWI385615B - Gamma correction device, display apparatus including the same, and method of gamma correction therein - Google Patents

Description

Karma correction component, display device including the same, and gamma correction method thereof

The present invention relates to a gamma correction device, a method of using the same, and a display device including the gamma correction device.

A variety of different types of flat panel display apparatuses have been widely used in daily life. In general, display devices can be classified into two main display types, emissive and non-emissive. Wherein, light-receiving (ie, non-radioactive) display devices include liquid crystal displays (LCDs), and light-emissive display devices include plasma display panels (plasma display panels, PDPs), electroluminescent displays (ELDs), light emitting diodes (LEDs), and vacuum fluorescent displays (VFDs). LCDs have been widely used in various applications of mobile devices because of their high image quality, brightness, lightness and shortness, and low power consumption.

1 is a functional block diagram of a general LCD device for illustrating an architecture applicable to a mobile unit. Referring to FIG. 1, the LCD device may include an LCD panel 10 for displaying image signals, and an LCD driver 190 for applying drive signals to the LCD panel 10.

Wherein, the LCD panel 10 is composed of a pair of transparent substrates and in which liquid crystal is injected (liquid Crystals) components. The gate lines are arranged on one of the transparent substrates at a fixed pitch, and the data lines are arranged at a fixed pitch in a direction perpendicular to the gate lines. In addition, thin film transistors (TFTs) are arranged in a matrix pattern on a region corresponding to the intersection of the gate line and the data line, and each of the thin film transistors corresponds to a pixel. On other areas of the transparent substrate, red (R, R), green (green), and blue (blue, B) color filters can be configured. On the back side of the LCD panel 10, a backlight (not shown) can be arranged as a uniform light source of the LCD panel 10. For example, a cold cathode fluorescent lamp (CCFL) can be used as a backlight source.

The LCD driver 190 includes a plurality of control circuits such as a gate driver 20 and a data driver 30, a timing controller 40, a gamma correction voltage generator 120, and a gray A gray-scale voltage generator 150, and the like. In a mobile unit, the LCD driver can be a single wafer.

The timing controller 40 generates control signals (eg, gate clock, gate open, etc.) required to operate the gate driver 20 and the data driver 30 in response to a clock signal CLK. The gray scale voltage generator 150 can output a plurality of gray scale voltages Vg used as reference values required to generate an LCD driving voltage. The gate driver 20 sequentially scans the pixels of each line on the LCD panel 10. The data driver 30 responds to the gray scale voltage Vg provided by the gray scale voltage generator 150, and is generated corresponding to the timing controller 40. The color signal RGB LCD drive voltage. The LCD driving voltage generated by the data driver 30 can be applied to an LCD panel every scanning period.

In the prior art, the optical transmission characteristics in the liquid crystal are not linearly related to the voltage level, and the luminance of the input gray scale is linearly changed. In other words, if the image data is changed, and/or the backlight brightness is changed, the image quality displayed on the LCD device 100 is also changed. Therefore, in order to provide improved and/or optimal image quality depending on the operating conditions, the gamma correction voltage generator 120 can be used to control the contrast and brightness of the image by adjusting the gamma characteristics. The conventional LCD device 100 shown in FIG. 1 can perform gamma correction by correcting the gamma voltage.

As a result of adjusting the gamma characteristic, the gamma correction voltage generator 120 outputs a plurality of (for example, eight) gamma correction voltages. The gray scale voltage generator 150 may receive the gamma correction voltage from the gamma correction voltage generator 120 and/or generate a gray scale voltage Vg having a plurality of defined voltage levels (eg, 64 steps). A technique for adjusting the contrast and/or brightness of an image using the gamma characteristic of the LCD device 100 is also referred to as "gamma correction". Among them, gamma (γ) is a gradient representing a line of data input value versus output value. The output value is defined by a relational expression of (input value) ^1/γ . For example, if the gamma value is 1.0, the input value will not change (ie, null transformation). If the gamma value is greater than 0.0 and less than 1.0, the image will be darkened. If the gamma value is greater than 1.0, the image will be brighter.

In order to correct the input/output characteristics of the display device, one of the gamma corrections The method is to provide a fixed gamma value for various types of display devices. For example, the National Television System Committee (NTSC) provides a gamma value of 2.2 for television, and Phase Alternate Line (PAL)/Sequential Color and Memory (Sequential Color and Memory, SECAM) provides a gamma value of 2.8 for TV. The gamma correction voltage corresponding to the gamma value (for example, the output luminance value as the input gray scale) may be arranged in a lookup table (LUT), and the values stored in the lookup table correspond to gray scales. Voltage.

However, since the above-described gamma correction method uses a fixed gamma value, it is difficult and/or almost impossible to apply to an environment in which image data changes and backlight brightness changes (for example, various changes in a display environment). To overcome these problems, the gamma voltage generator 120 can include a plurality of lookup tables corresponding to a plurality of gamma values. However, because the look-up table must store offset values that apply to all grayscale voltages, a significant number of registers must be provided, thus increasing the die size.

Furthermore, to provide a look-up table suitable for various gamma values, the manufacturer must measure the grayscale value corresponding to each gamma value to be stored in the scratchpad. Therefore, as the number of gamma values increases, the time and cost used to determine the value to be stored in the scratchpad will also increase.

In view of this, the embodiments of the present invention provide a gamma correction device and a gamma correction method. The gamma correction device and method provided by the preferred embodiment of the present invention perform microscopic calculation according to changes in image data and backlight brightness under the condition that the wafer size and the cost of the gamma correction device can be reduced and/or reduced. Karma correction. The gamma correction device can be applied to, for example, a mobile unit because it can reduce and/or reduce the size of the wafer and/or reduce the complexity of the gamma correction device, and provides the advantages of lightness, thinness, and better power consumption efficiency. Device.

According to a preferred embodiment of the present invention, the present invention provides a gamma correction method. The method includes the steps of: generating a plurality of gamma correction voltages corresponding to a reference gamma value; dividing the gamma correction voltages to generate a plurality of sub gray-scale voltages, and the sub-grey The step voltage corresponds to a plurality of gamma values including reference gamma values; and outputs a sub-gray voltage corresponding to one of the gamma values.

According to a preferred embodiment of the present invention, the present invention provides a gamma correction method. The method includes the steps of: generating a plurality of gamma correction voltages corresponding to a reference gamma value; dividing the gamma correction voltages to generate a plurality of sub-gray voltage groups, wherein each sub-gray voltage group includes a corresponding a sub-gray voltage of each gamma value; and one of the sub-gray voltages of each sub-gray voltage group is output as a gray scale voltage.

According to a preferred embodiment of the present invention, the present invention provides a gamma correction device. The gamma correction device includes: a gamma correction voltage generator for generating a plurality of gamma correction voltages corresponding to a reference gamma value; and a gray scale voltage generation circuit for dividing the gamma correction voltages, Generating a plurality of sub-gray voltages corresponding to a plurality of gamma values including the reference gamma value; and a gray scale voltage selection circuit for outputting a value corresponding to one of the gamma values A sub-gray voltage.

According to a preferred embodiment of the present invention, the present invention provides a gamma correction Device. The gamma correction device includes: a gamma correction voltage generator for generating a plurality of gamma correction voltages corresponding to a reference gamma value; and a gray scale voltage generation circuit for dividing the gamma correction voltages, Generating a plurality of sub-gray voltage groups, wherein each sub-gray voltage group includes a sub-gray voltage corresponding to each gamma value; and a gray-scale voltage selection circuit for each sub-gray voltage One of the sub-gray voltages of the group is output as a gray scale voltage.

According to a preferred embodiment of the present invention, the present invention provides a display device. The display device includes: a gamma correction voltage generator for generating a plurality of gamma correction voltages corresponding to a reference gamma value; and a gray scale voltage generation circuit for dividing the gamma correction voltages to generate a plurality of sub-gray voltages, and the sub-gray voltages correspond to a plurality of gamma values including the reference gamma value; a gray-scale voltage selection circuit for outputting a sub-grey corresponding to one of the gamma values The step voltage; a driver that responds to the image data and the output sub-gray voltage to generate a driving voltage for displaying the image data; and a display panel that displays the image data in response to the driving voltage.

According to a preferred embodiment of the invention, the reference gamma value controls the gamma correction voltage to be generated in a uniform manner.

In accordance with a preferred embodiment of the present invention, the gamma correction voltage is generated in response to a plurality of deviation values corresponding to the reference gamma value and a plurality of deviation values defined by the user.

According to a preferred embodiment of the invention, the sub-grayscale voltage can be generated by dividing the voltage-dividing points again.

According to a preferred embodiment of the present invention, the number of sub-gray voltages can be more than Produced by a resistor of the sub-gray voltage.

According to a preferred embodiment of the invention, the gray-scale voltage is the result of performing a gamma correction based on one of the gamma values.

In accordance with a preferred embodiment of the present invention, the gray scale voltage may vary depending on user input, display, and environmental changes in the image signal and/or display pattern.

In accordance with a preferred embodiment of the present invention, a look-up table associated with a gamma value and/or additional circuitry for adjusting the gamma correction voltage may not be required.

The above and other objects, features and advantages of the present invention will become more <

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Wherein the same reference numbers represent the same elements.

Although the preferred embodiment of the invention can have various different modifications, the embodiments thereof will be described in detail herein with reference to the accompanying drawings. However, those skilled in the art will recognize that the invention is not limited to the specific types of embodiments set forth herein, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application attached. In the drawings appended with the present invention, the same functional elements are denoted by the same reference numerals.

Although the terms first, second, etc. are used herein to describe various elements, it is understood that the elements are not limited to the terms. These nouns are only used to distinguish the component from other components. For example, the first component is also May be the second component. Similarly, the second component may also be the first component without departing from the scope of the invention. The term "and/or" used hereinafter includes any and all combinations of one or more of the associated listed elements.

When it is described below that an element is "connected" or "coupled" to other elements, it can be directly connected or coupled to the other elements, or the other elements can be inserted. In contrast, when an element is referred to as "directly connected" or "directly coupled" to another element, it is not. Other terms used to describe the relationship between elements, such as "between" relative to "directly between", "adjacent" relative to "directly adjacent", Etc., should also be explained in the same way.

The terminology used herein is for the purpose of describing particular embodiments only, Unless otherwise stated, the singular noun "a" or "the" or "the" The terms "comprises" or "includes" or "includes" or "includes" are used to indicate the stated features, integers, steps, operations. The existence of elements, elements, and/or components, but does not exclude the presence or addition of one or more other properties, integers, steps, acts, components, components, and/or groups thereof.

It will be apparent that in some embodiments of the invention, the functions/acts may occur in a different order than shown. For example, the figure appears in order The two graphics may in fact be executed simultaneously or in reverse order, depending on the desired function/action.

According to a preferred embodiment of the present invention, a gamma correction device and method thereof are included in an LCD device and are configured to fix a gamma correction voltage and generate a gray scale voltage corresponding to a plurality of gamma values. Way to adjust the output range of the grayscale voltage. According to a preferred embodiment of the present invention, the gamma correction corresponding to various gamma values can be performed by adjusting the output range of the gray scale voltage.

2 is a functional block diagram of an LCD device 200 in accordance with a preferred embodiment of the present invention. The LCD device 200 can generate a gray scale voltage corresponding to a plurality of gamma values by adjusting an output range of the gray scale voltage when a gamma value is fixed at a fixed level. Although FIG. 2 corresponds to a particular mobile LCD device 200, the present invention is also applicable to a variety of non-mobile display devices (eg, televisions, monitors, etc.). Furthermore, the present invention is also applicable to other display devices such as PDP, ELD, LED, VFD, and the like.

The LCD device 200 shown in Fig. 2 is similar to the circuit structure shown in Fig. 1. Therefore, for simplification of the description, there are various components of the LCD device described above with reference to FIG. 1, and details will not be described herein.

Referring to FIG. 2, the Karma correction voltage generator 220 can output a plurality of gamma correction voltages. For example, based on a gamma value reference value (eg, 1.0), eight gamma correction voltages can be output to provide optical transmittance that varies linearly with the voltage of the LCD panel 10. According to an embodiment of the invention, if the gamma value is 1.0, the input/output image data is input. There is no change, and this situation becomes a null transformation. The gamma correction voltage output from the gamma correction voltage generator 220 can be fixed at a fixed level, and the gray scale voltage generator 250 according to a preferred embodiment of the present invention can be used to specifically perform the gamma correction operation.

FIG. 3 is a detailed block diagram of a gamma correction voltage generator 220 as shown in FIG. 2. Referring to FIG. 3, the gamma correction voltage generator 220 may include a reference gamma register set 221 and a user-specific gamma register set 223. A data selection circuit 225, and a gamma adjustor 227. The reference gamma register set 221 can store, for example, gamma correction deviation data corresponding to a reference gamma value having a value of 1.0, wherein the deviation data corresponds to a gray scale voltage. The user specific gamma register set 223 can store, for example, gamma correction deviation data as defined by the manufacturer of the mobile unit. The deviation data stored in the user-specific gamma register group 223 corresponds to the gray scale voltage.

The data selection circuit 225 outputs the deviation data from the reference gamma register group 221 and/or the user-specific gamma register group 223 in response to an automatic gamma activation signal Auto_Gamma_En. For example, when the automatic gamma activation signal Auto_Gamma_En is set to "1", the data selection circuit 225 can output the deviation data from the reference gamma register group 221. When the automatic gamma activation signal Auto_Gamma_En is set to "0", the material selection circuit 225 can output the deviation data from the user-specific gamma register group 223. Among them, the automatic gamma start signal Auto_Gamma_En can be transmitted by the user through the LCD An interface (not shown) of the driver 290 is input directly and/or indirectly. In addition, the automatic gamma start signal Auto_Gamma_En can also be designed to automatically adjust according to changes in image data and backlight brightness.

For example, the gamma regulator 227 can generate eight gamma correction voltages in response to the gamma correction deviation data provided by the data selection circuit 225 and the power supply voltage VDD. The LCD device 200 can operate in an analog drive mode. In the analog drive mode, positive image data is applied to the pixels within a time interval T, and negative image data is applied to the pixels within the next time interval T, thereby displaying Next image frame. Therefore, the gamma correction voltage generator 220 can alternately generate eight gamma correction voltages VINP0/VINN0~VINP7/VINN7.

Referring to FIG. 2, the gray scale voltage generator 250 may include a gray scale voltage generating circuit 230 and a gray scale voltage selecting circuit 240. The gray scale voltage generating circuit 230 can receive the gamma correction voltages VINP0 / VINN0 ~ VINP7 / VINN7 and output a sub-gray voltage group corresponding to the gray scale level. Each of the sub-gray voltage groups may include a plurality of sub-gray voltages corresponding to a plurality of gray scale values. The gray scale voltage generating circuit 240 selects one of the sub gray scale voltages in each of the sub gray scale voltage groups in response to a gray scale selection signal Gamma_Sel. One of the selected sub-gray voltages is treated as a corrected grayscale voltage output. The gray scale voltage generated by the gray scale voltage generator 250 can be divided into a plurality of levels. For example, the gray scale voltage generated by the gray scale voltage generator 250 can be divided into 64 (or 256) levels. In 64 gray scale voltages, The first and last grayscale voltages, such as Vg0 and Vg63, correspond to black and white data, respectively. Therefore, the first and last gray scale voltages can be directly output to the data driver 30 without any other processing.

In accordance with a preferred embodiment of the present invention, the gray scale voltage can be varied to various levels under a fixed gamma voltage. Therefore, the gamma correction can be performed by selecting one of the gray scale voltages.

4 is a detailed circuit diagram of a gray scale voltage generating circuit 230 as shown in FIG. 2 in accordance with a preferred embodiment of the present invention.

Referring to FIG. 4, the gray scale voltage generating circuit 230 may include a plurality of voltage followers 231 to 238, and a plurality of resistors applied by the voltage followers 231 to 238 to divide the gamma correction voltage. VINP0/VINN0~VINP7/VINN7. The voltage followers 231~238 can receive the gamma correction voltages VINP0/VINN0~VINP7/VINN7 from the gamma correction voltage generator 220. Each voltage follower can be an amplification circuit that operates at a gain of one. The voltage followers 231~238 can amplify the current without changing the voltage. Therefore, the voltage loss caused by the internal resistance can be reduced, and/or the impedance of the input signal can be reduced, thereby improving the signal-to-noise ratio (SNR) of the device.

In accordance with a preferred embodiment of the present invention, the resistors connected to the voltage followers 231-238 are connected in series with each other in the manner shown in FIG. For example, the gamma correction voltage can be divided by a resistor, for example, via the gamma correction voltages VINP0/VINN0~VINP7/VINN7 provided by the voltage followers 231~238 to generate a majority of the gray scales. Pressure. An example architecture for a circuit that produces a gray scale voltage using a plurality of resistors is disclosed in U.S. Patent No. 6,067,063 issued May 2, 2000 by Kim et al. entitled "LIQUID CRYSTAL DISPLAY HAVING A WIDE VIEW" ANGLE AND METHOD FOR DRIVING THE SAME", and this document is incorporated herein by reference.

A gray scale voltage generating circuit according to a preferred embodiment of the present invention can provide a plurality of sub-gray voltages V1, V1a, and V1b. For example, the voltages V0 V V63 in FIG. 4 may be sub-gray voltages corresponding to a gamma value of 1.0. The voltages V0 to V63 may be similar to and/or identical to the gray scale voltages generated when the gamma value is set to 1.0. Details of the generation of the gray scale voltage using the gray scale voltage generating circuit 230 will be described in detail below.

FIG. 5 is a detailed circuit diagram of a portion of the circuitry included in the dashed box 2320 of FIG. Referring to FIG. 5, the gray scale voltage generating circuit 230 can provide a plurality of sub-gray voltages V1/V1a/V1b/V1c, V2/V2a/V2b/V2c, and the like, wherein each sub-gradation voltage is also referred to as a Sub-gray voltage group. The number of sub-gray voltage groups will be proportional to the resolution depth of the display device. The sub-gray voltages belonging to each sub-gray voltage group, such as V1, V1a, V1b, and V1c, may correspond to different gamma values. For example, the sub-gray voltage V1 may correspond to a gamma value of 1.0, the sub-gray voltage V1a may correspond to a gamma value of 1.8, the sub-gray voltage V1b may correspond to a gamma value of 2.2, and the sub-gray scale The voltage V1c may correspond to a gamma value of 2.5.

According to a preferred embodiment of the present invention, the difference between adjacent gray scale voltages May be different. Therefore, the resistance value used to establish the gray scale voltage also varies. For example, resistor 14R (where R is a unit resistance) can be connected between adjacent voltage terminals V1 and V2, and resistor 7R can be connected between adjacent voltage terminals V2 and V3. Further, in accordance with a preferred embodiment of the present invention, the gray scale voltage generating circuit may include a plurality of resistors having the same resistance value for reducing the error of the division value without using a plurality of resistors having different resistance values. For example, each of them has 14 unit resistors with a unit resistance value of R, which can be connected in series between voltage terminals V1 and V2, and 7 unit resistors can be connected in series at voltage terminals V2 and V3. between.

In accordance with a preferred embodiment of the present invention, the voltage splitting point can be split again and used to generate a plurality of sub-gray voltage groups corresponding to a plurality of gamma values. In other words, in a preferred embodiment of the invention, the voltage splitting point can be split again into smaller cells, and then a plurality of sub-gray voltages are generated without adding a new circuit to the sub-gray voltage. As described above, the sub-gray voltage group can refer to a plurality of sub-gradation voltages generated when a gamma voltage is applied. The steps of determining the sub-gray voltage level are described in detail below.

Figure 6 is a graph showing the relationship between the gray level and the light transmittance of different gamma values. Figure 6 is a graph including gamma values of 1.0, 1.8, 2.2, and 2.5.

Please refer to Figure 6. The V30 voltage generated when the gamma value is 1.8 may be exactly the same as the V17 voltage generated when the gamma value is 1.0. In addition, the V30 voltage generated when the gamma value is 2.5 may be exactly the same as the V10 voltage generated when the gamma value is 1.0. therefore, When the gamma value changes from 1.8 to 1.0, the grayscale voltage changes from V30 to V17. Furthermore, when the gamma value changes from 2.5 to 1.0, the grayscale voltage changes from V30 to V10.

As shown in the example of FIG. 6, when the gamma value is 1.0, the voltages V30, V17, V13, and V10 may correspond to variations in the gamma value of 1.0 to 1.8, 2.2, or 2.5 on the V30 voltage. The preferred embodiment of the present invention utilizes the correlation of the gamma curves by assigning gray scale voltages corresponding to different gamma values to grey scale voltages designated as a reference gamma value, such as 1.0. Furthermore, the preferred embodiment of the invention determines the voltage division point to obtain a corresponding voltage using a resistor. Therefore, a plurality of gray scale voltages associated with different gamma values can be generated by adjusting the output range of the gray scale voltage generated with the reference gamma value, for example, 1.0, as is the case from the gamma correction voltage generator 220. Produce in general.

As shown in Fig. 6, the gray scale voltages V0 to V63 generated when the gamma value is 1.0 may be different from the gray scale voltage generated when the gamma value is not 1.0. Therefore, in order to use the grayscale voltage of the gamma value different from the reference gamma value, which is exactly the same as the grayscale voltage assigned to the 1.0 gamma value, a preferred embodiment of the present invention can provide the sub-gray voltage group V1a~ V1c, V2a~V2c, and the like, and the sub-gray voltage groups can be further divided into the gray scale voltages V0 to V63 defined above. According to a preferred embodiment of the present invention, the additional sub-gray voltage groups V1a-V1c, V2a-V2c can be generated by dividing the voltage division points arranged between the plurality of resistors again.

Referring to FIG. 2, a plurality of sub-gray voltage groups provided by the gray-scale voltage generating circuit 230 can be input to the gray-scale voltage selecting circuit 240. The gray scale voltage selection circuit 240 selects one of the sub-gray voltages in each of the sub-gray voltage groups in response to a gamma selection signal Gamma_Sel. One of the selected sub-gray voltages can be treated as a modified gray scale voltage output.

FIG. 7 is a detailed circuit diagram of a gray scale voltage selection circuit 240 as shown in FIG. 2. Referring to FIG. 7, the gray scale voltage selection circuit 240 may include a plurality of data selection circuits 241 to 2462. Each of the data selection circuits 241~2462 includes an N:1 multiplexer for selecting one of the N data bits in response to a gamma selection signal Gamma_Sel. Each of the data selection circuits 241 to 2462 is responsive to a gamma selection voltage Gamma_sel to selectively drive one of the sub-gray voltages in each of the sub-gray voltage groups. For example, when the gamma value is 1.0, a "00" gamma selection signal Gamma_Sel is specified to select a sub-gray voltage (for example, V1); when the gamma value is 1.8, a "01" is specified. The gamma selects the signal Gamma_Sel to select a sub-gray voltage (eg V1a); when the gamma value is 2.2, a “10” gamma selection signal Gamma_Sel is specified to select a sub-gray voltage (eg V1b); and when the gamma value is 2.5, an "11" gamma selection signal Gamma_Sel is specified to select a sub-gray voltage (for example, V1c). The sub-gray voltage selected by the data selection circuits 241 to 2462 is output as the corrected gray-scale voltages Vg1 to Vg62 as a result of the gamma correction. According to a preferred embodiment of the present invention, the gamma selection signal Gamma_Sel having various data codes can be directly and/or indirectly input by a user using an interface (not shown) included in the LCD driver 290, and/or Automatic production In order to output a grayscale voltage when the image data changes and/or the backlight brightness changes.

FIG. 8 is a flow chart for explaining a gamma correction method according to a preferred embodiment of the present invention.

Referring to FIG. 8, a gamma correction method according to a preferred embodiment of the present invention can generate a plurality of gamma correction voltages VINP0/VINN0~VINP7/VINN7. First, the gamma correction voltage generator 200 generates the gamma correction voltages VINP0/VINN0~VINP7/VINN7 according to a reference gamma value, such as γ=1.0 (step 2200). Next, the gray scale voltage generating circuit 230 divides the gamma correction voltages VINP0/VINN0~VINP7/VINN7 into a plurality of sub-gray voltages having 64 or 256 levels, and generates a plurality of sub-gradation voltage groups V1~ V1c, V2~V2c, etc. (step 2300). Each of the sub-gray voltage groups may include a sub-gray voltage that is assigned a gamma value (eg, γ=1.0, γ=1.8, γ=2.2, and γ=2.5). The gray scale voltage generating circuit can select one of the sub gray scale voltages in each of the sub gray scale voltage groups. Finally, the gray scale voltage selection circuit 240 can select the sub gray scale voltage selected from the sub gray scale voltage groups V1 VV1c, V2 VV2c, and the like as a corrected gray scale voltage Vg1, Vg2, etc. (Step 2400).

As described above, the gamma correction device and method provided by the present invention can utilize the gamma curve characteristic to generate a plurality of sub-gray voltages according to gray level levels, and perform an efficient gamma correction operation. In other words, the gray scale voltage corresponding to a plurality of gamma values can be generated by fixing the gamma correction voltage at a fixed level and adjusting the output range of the gray scale voltage.

While the invention has been described above by way of a preferred embodiment, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

10‧‧‧LCD panel

20‧‧ ‧ brake driver

30‧‧‧Data Drive

40‧‧‧Timing controller

100‧‧‧LCD device

120‧‧‧ 珈玛修正 voltage generator

150‧‧‧ Grayscale voltage generator

190‧‧‧LCD Driver

200‧‧‧LCD device

220‧‧‧珈玛修正 voltage generator

221‧‧‧Refer to the Karma Register

223‧‧‧User-specific register group

225‧‧‧ data selection circuit

227‧‧‧ gamma regulator

230‧‧‧ Gray scale voltage generating circuit

231~238‧‧‧Voltage mate

2320‧‧‧dotted box

240‧‧‧ Gray scale voltage selection circuit

241~2462‧‧‧ data selection circuit

250‧‧‧ Grayscale voltage generator

290‧‧‧LCD Driver

2200‧‧‧ Generates a gamma voltage suitable for the gamma value

2300‧‧‧ Generate sub-gray voltage groups for grayscale voltages

2400‧‧‧ Generate a grayscale voltage as one of the sub-gray voltages in each sub-gray voltage group

FIG. 1 is a functional block diagram of a conventional liquid crystal display device.

2 is a functional block diagram of a liquid crystal display device in accordance with a preferred embodiment of the present invention.

3 is a detailed block diagram of a gamma correction voltage generator as shown in FIG. 2 in accordance with a preferred embodiment of the present invention.

4 is a detailed circuit diagram of a gray scale voltage generating circuit as shown in FIG. 2 in accordance with a preferred embodiment of the present invention.

FIG. 5 is a detailed circuit diagram of a portion of the circuitry included in the dashed box of FIG. 4 in accordance with a preferred embodiment of the present invention.

Figure 6 is a graph showing an example of gamma values of 1.0, 1.8, 2.2, and 2.5 in accordance with a preferred embodiment of the present invention.

FIG. 7 is a detailed circuit diagram of a gray scale voltage selection circuit shown in FIG. 2 according to a preferred embodiment of the present invention.

FIG. 8 is a flow chart for explaining a gamma correction method according to a preferred embodiment of the present invention.

10‧‧‧LCD panel

20‧‧ ‧ brake driver

30‧‧‧Data Drive

40‧‧‧Timing controller

200‧‧‧LCD device

220‧‧‧珈玛修正 voltage generator

230‧‧‧ Gray scale voltage generating circuit

240‧‧‧ Gray scale voltage selection circuit

250‧‧‧ Grayscale voltage generator

290‧‧‧LCD Driver

Claims (32)

A method for modifying a gamma, comprising: selecting a plurality of deviation values from a reference gamma register or a user-specific gamma register in response to an automatic gamma activation signal; the response corresponding to at least one of the majority of gamma values Selecting the deviation values to generate a plurality of gamma correction voltages; dividing the gamma correction voltages to generate a plurality of sub-gray voltages, wherein the sub-gray voltages correspond to the gamma values; Outputting a sub-gray voltage corresponding to one of the gamma values, wherein the reference gamma register is configured to store a plurality of values corresponding to a reference gamma value, and the user-specific gamma register is configured to store Most of the values defined by the user. The gamma correction method of claim 1, wherein the sub-gray voltages are generated at a plurality of voltage division points arranged between the plurality of resistors. The gamma correction method of claim 2, wherein the sub-gray voltages are generated by dividing the voltage division points again. The method of modifying the gamma according to claim 1, wherein the reference gamma value controls the gamma correction voltage to be generated in a uniform manner. The method of modifying the gamma as described in claim 1, wherein the automatic gamma activation signal is received from the user. The method for correcting the gamma as described in claim 1, wherein the automatic gamma activation signal is based on the brightness of the image signal and a display. The change is automatically determined. The method of modifying the gamma according to claim 1, wherein the number of the gray scale voltages is proportional to a resolution of a display unit. The method for modifying a gamma according to claim 1, wherein the step of dividing the gamma correction voltages to generate the sub-gray voltages comprises: avoiding voltage loss in the gamma correction voltages; And dividing the gamma correction voltages, wherein the sub-gray voltages are generated at a plurality of voltage division points arranged between the plurality of resistors. The gamma correction method of claim 8, wherein the sub-gray voltages are generated by dividing the voltage division points again. The method of modifying the gamma according to item 8 of the patent application, wherein the step of dividing the gamma correction voltages is performed by using a plurality of resistors having a number more than the number of the sub-gray voltages. The gamma correction method as described in claim 1, wherein the gray scale voltage is a result of performing a gamma correction according to one of the gamma values. The gamma correction method of claim 1, wherein the step of outputting one of the sub-gray voltages comprises outputting the sub-gray voltage corresponding to one of the gamma values according to a gamma selection signal. The method of modifying the gamma as described in claim 12, wherein the gamma selection signal is changed according to an input of the user. The method for correcting the gamma as described in claim 12, The gamma selection signal will change according to a display. For example, in the method of modifying the gamma described in claim 12, the gamma selection signal changes according to changes in the image signal or the display pattern. A gamma correction device comprising: a gamma correction voltage generator for selecting a plurality of offset values from a reference gamma register or a user specific gamma register in response to an automatic gamma activation signal And generating a plurality of gamma correction voltages in response to the offset values corresponding to at least one of the plurality of gamma values being selected; a gray scale voltage generating circuit for dividing the gamma correction voltages to generate a plurality of sub-gray voltages, wherein the sub-gray voltages correspond to the gamma values; and a gray-scale voltage selection circuit for outputting a sub-gray voltage corresponding to one of the gamma values, wherein the The reference gamma register is used to store a plurality of values corresponding to a reference gamma value, and the user-specific gamma register is used to store a plurality of values defined by the user. The gamma correction device of claim 16, wherein the sub-gray voltages are generated at a plurality of voltage division points arranged between the plurality of resistors. The gamma correction device of claim 17, wherein the sub-gray voltages are generated by dividing the voltage division points again. The gamma correction device as described in claim 16 of the patent application, The reference gamma value controls the gamma correction voltages to be generated in a uniform manner. The gamma correction device according to claim 16, wherein the number of the gray scale voltages is proportional to a resolution of a display unit. The gamma correction device according to claim 16, wherein the gray scale voltage generator comprises: a voltage follower to avoid voltage loss in the gamma correction voltage; and a plurality of resistors, The gamma voltages are divided, wherein the sub-gray voltages are generated at a plurality of voltage division points arranged between the resistors. The gamma correction device of claim 21, wherein the sub-gray voltages are generated by dividing the voltage division points again. The gamma correction device of claim 21, wherein the gray scale voltage generating circuit comprises the resistors having a number more than the number of the sub-gray voltages. The gamma correction device according to claim 16, wherein the gray scale voltage is a result of performing a gamma correction according to one of the gamma values. The gamma correction device of claim 16, wherein the gray scale voltage selection circuit comprises a plurality of data selection circuits responsive to a gamma selection signal, and outputting the sub-gray level corresponding to one of the gamma values Voltage. The gamma correction device of claim 25, wherein the gamma selection signal is changeable according to an input of a user. For example, the gamma correction device described in claim 25, wherein the gamma selection signal can be changed according to a display. For example, the gamma correction device described in claim 25, wherein the gamma selection signal can be changed according to changes in the image signal or the display pattern. A display device includes: a gamma correction device; a driver responsive to an image data and an output sub-gray voltage, generating a driving voltage to display the image data; and a display panel responsive to the driving voltage, displaying the Image data, wherein the gamma correction device comprises: a gamma correction voltage generator for selecting a majority from a reference gamma register or a user specific gamma register in response to an automatic gamma activation signal An offset value, and a response corresponding to at least one of the plurality of gamma values to generate a plurality of gamma correction voltages; a gray scale voltage generation circuit for dividing the gamma correction a voltage to generate a plurality of sub-gray voltages, wherein the sub-gray voltages correspond to the gamma values; and a gray-scale voltage selection circuit for outputting a sub-gray voltage corresponding to one of the gamma values The reference gamma register is configured to store a plurality of values corresponding to a reference gamma value, and the user-specific gamma register is used to store Save most of the values defined by the user. The display device of claim 29, wherein the sub-gray voltages are generated at a plurality of voltage division points arranged between the plurality of resistors. The display device of claim 30, wherein the sub-gray voltages are generated by dividing the voltage division points again. The display device of claim 29, wherein the reference gamma value controls the gamma correction voltages to be generated in a uniform manner.